Washington, D.C. ? The $600 rebate checks provided by the federal stimulus package earlier this year may have been popular among taxpayers, but many economists think any future effort should focus on infrastructure spending and other targeted measures.

Spending on new roads, bridges and other public works projects would create jobs and provide more of a lasting boost to the economy than another round of rebate checks, several economists said. They contend a common concern about infrastructure spending – that it takes time to gear up and may not kick in until after the recession is over – is less compelling now because the U.S. economy likely will experience an extended downturn.

“We’re going to be in a longer period of weak growth and high unemployment” than was expected earlier this year, said Laurence Meyer, vice chairman of Macroeconomic Advisers and a former Federal Reserve governor. Any new stimulus needs to “have more legs” than the rebate checks, he said.

House Speaker Nancy Pelosi of California and fellow congressional Democrats are pushing a new stimulus package that could cost as much as $150 billion, though some economists think the total should be $300 billion or higher.